Vermikomposztálás, mint a szennyvíziszap-komposztálás alternatív megoldása ─ Szemle ─ = Vermicomposting as an alternative way of composting sewage sludge

Agricultural utilisation is one of the most promising uses of sewage sludge in Hungary. Sewage sludge can be applied to agricultural fields in two ways: the injection of dewatered sewage sludge and the application of sewage sludge after composting. Vermicomposting is a special type of composting, where the organic residues are broken down by earthworms. The worms facilitate the decomposition process both by mixing the sludge and by physically degrading it. Earthworm species have various morphotypes requiring different habitats. Compost worms have great adaptability to extreme conditions and are capable of exploiting organic matter in a state of decomposition. Eisenia sp., Eudrilus eugeniae and Perionyx excavatus are important species for vermicomposting. When examining the role and possibilities of vermicomposting, it is important to compare it with traditional composting methods. The most important aspect of producing vermicompost is to ensure optimum environmental conditions for the earthworms, especially in terms of temperature, humidity and aeration, which requires constant attention. An important feature of traditional composting is the thermophilic phase, during which the pathogenic organisms in sewage sludge are destroyed. The thermophilic phase is omitted during vermicomposting due to the thermal sensitivity of the earthworms, but the presence and activity of the earthworms results in similar sterility. Regarding its nutrient content, vermicompost contains larger quantities of total and plant-available macroelements than conventional composts. A further advantage is the presence of the plant hormone agents excreted by earthworms. From the environmental point of view, the ability of earthworms to accumulate heavy metals and the role of their special gut flora in the decomposition of organic pollutants could contribute to the wider use of vermicomposting to dispose of sewage sludge. While vermicompost has many advantages, a number of obstacles need to be overcome before it can be routinely used in Hungary. Many landowners regard sewage sludge compost as hazardous waste that could contaminate their soil and crops rather than as a nutrient and soil amendment. Although numerous studies have been published on sewage sludge, the assessment of long-term effects, including the issues currently of most concern in Hungary, is still lacking. Vermicomposting is therefore a promising, innovative technology for sewage sludge recycling. Sewage sludge and sewage sludge composts with pollutant contents greater than the limits laid down in Government Regulation 50/2001. (IV.3.) can be made suitable for agricultural use by vermicomposting

Effect of composting and vermicomposting on potentially toxic element contents and bioavailability in sewage sludge digestate

Vermicomposts and composts prepared from sewage sludge digestate and additives (spent mushroom compost, straw, biochar) after 43 days pre-composting followed by 90 days vermicomposting with Eisenia fetida or by compost maturing were investigated regarding the potentially toxic element (PTE) As, Co, Cr, Cu, Mo, Ni, Pb and Zn contents. The average increment in the total PTE concentration for the entire process was ten times higher (104 %) compared to the increment solely in the composting or vermicomposting (9.3 and 9.5 %, respectively) after pretreatment. Compared to the untreated digestate the As and Co concentrations in the final mixtures were 26 and 51 % higher, respectively while for the other PTEs 26 ± 9 % average decrease was observed. Total PTE content was the same in composts and vermicomposts. Average PTE bioavailability (water soluble/total concentration) was statistically the same in vermicomposts (2.5) and composts (2.7), but lower in mixtures with biochar (2.5) than without it (2.8).publishedVersio

Use of biochar for green roofs

Green roofs are increasingly being used to meet the challenges of extreme rainfall and surface water management in cities and towns. Biochar is a locally sourced and carbon-negative material that can be used as a substrate component for green roofs. Here are some experiences NIBIO has gained in this area through research and testing of various concept.publishedVersio

Plast i jord

Resirkulering av organisk avfall er et prioritert tema innen sektorene landbruk, klima og avfall, og skal bidra til at organisk materiale og næringsstoffer føres tilbake til jord. Dette kan motvirke en langsiktig trend der moldinnholdet i matjorda gradvis blir lavere, noe som ser ut til å bli et økende problem i forbindelse med klimaendringer og økende behov for mat. Tilbakeføring av næringsstoffene i organisk avfall skal på sin side bidra til å redusere behovet for mineralgjødsel, og dermed minske behovet for energikrevende gjødselproduksjon og uttømming av begrensete ressurser av mineralsk fosfat

Plast i jord

Resirkulering av organisk avfall er et prioritert tema innen sektorene landbruk, klima og avfall, og skal bidra til at organisk materiale og næringsstoffer føres tilbake til jord. Dette kan motvirke en langsiktig trend der moldinnholdet i matjorda gradvis blir lavere, noe som ser ut til å bli et økende problem i forbindelse med klimaendringer og økende behov for mat. Tilbakeføring av næringsstoffene i organisk avfall skal på sin side bidra til å redusere behovet for mineralgjødsel, og dermed minske behovet for energikrevende gjødselproduksjon og uttømming av begrensete ressurser av mineralsk fosfat.publishedVersio

Bruk av biokull til grønne tak

Grønne tak tas i bruk i økende grad for å møte utfordringene med ekstrem nedbør og håndtering av overvann i byer og tettsteder. Biokull er et kortreist og karbonnegativt materiale som kan brukes som en komponent i jord til grønne tak. Her er noen erfaringer NIBIO har gjort på dette området gjennom forskning og utprøving av ulike konsepter

Use of biochar for green roofs

Green roofs are increasingly being used to meet the challenges of extreme rainfall and surface water management in cities and towns. Biochar is a locally sourced and carbon-negative material that can be used as a substrate component for green roofs. Here are some experiences NIBIO has gained in this area through research and testing of various concept

Bruk av biokull til grønne tak

Grønne tak tas i bruk i økende grad for å møte utfordringene med ekstrem nedbør og håndtering av overvann i byer og tettsteder. Biokull er et kortreist og karbonnegativt materiale som kan brukes som en komponent i jord til grønne tak. Her er noen erfaringer NIBIO har gjort på dette området gjennom forskning og utprøving av ulike konsepter.publishedVersio

Co-composting of digestate and garden waste with biochar: effect on greenhouse gas production and fertilizer value of the matured compost

Biogas digestate is a nitrogen (N) rich waste product that has potential for application to soil as a fertilizer. Composting of digestate is recognized as an effective step to reduce potentially negative consequences of digestate application to soils. However, the structure of the digestate and the high N content can hinder effective composting. Biochar, which can be produced through the pyrolysis of waste biomass, has shown the potential to improve compost structure and increase N retention in soils. We studied how a high-temperature wood biochar affects the composting process, including greenhouse gas emissions, and the fertilizer value of the compost product including nutrient content, leachability and plant growth. The high Biochar dose (17% w/w) had a significantly positive effect on the maximum temperature (5°C increase vs. no biochar) and appeared to improve temperature stability during composting with less variability between replicates. Biochar addition reduced cumulative N2O emission by 65–70%, but had no significant effect on CO2 and CH4 emission. Biochar did not contribute to greater retention of nitrogen (N) contained in the digestate, but had a dilution effect on both N content and mineral nutrients. Fertilization with compost enhanced plant growth and nutrient retention in soil compared to mineral fertilization (NPK), but biochar had no additional effects on these parameters. Our results show that biochar improves the composting of digestate with no subsequent negative effects on plants.publishedVersio

Planteproduksjon på alunskiferjord

NIBIO har overvåket og vurdert risikoaspektene ved tungmetallopptak i matplanter gjennom et kunnskapsutviklingsprosjekt som rapporteres her. NIBIO foreslår at det foretas en systematisk kartlegging av alunskiferjord basert på kjemiske analyser. Dette vil dokumentere omfanget samt redusere risiko for overskridelser ved å øke forutsigbarheten for dyrkere. Videre vil det være et viktig grunnlag for å vurdere hvordan EUs nye grenseverdier kan håndteres i Norge, herunder situasjoner med grønsaksavlinger som overskrider grenseverdiene. Sistnevnte vil være av stor betydning for grønnsaksprodusenter i alunskiferområder.Planteproduksjon på alunskiferjordpublishedVersio